Illumination device and display unit

ABSTRACT

A first illumination device includes a light source that emits light having directivity, and a uniform illumination optical system including a first fly-eye lens that includes a plurality of lenses two-dimensionally arranged and allows light based on emitted light from the light source to pass through the first fly-eye lens. An illumination target region has a planar shape having a side extending along a direction substantially parallel to a long-axis direction or a short-axis direction of an intensity distribution shape of emitted light from the light source, and a periodic direction of an array of the lenses in the first fly-eye lens is inclined with respect to the long-axis direction or the short-axis direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims the benefit under 35U.S.C. § 120 of U.S. patent application Ser. No. 15/511,024, titled“ILLUMINATION DEVICE AND DISPLAY UNIT,” filed on Mar. 14, 2017, now U.S.Pat. No. 10,146,118, which is a National Stage of InternationalApplication No. PCT/JP2015/075702, filed in the Japanese Patent Officeas a Receiving office on Sep. 10, 2015, which claims priority toJapanese Patent Application Number 2014-196721, filed in the JapanesePatent Office on Sep. 26, 2014, each of which is hereby incorporated byreference in its entirety.

TECHNICAL FIELD

The present disclosure relates to an illumination device using, forexample, a solid-state light-emitting element such as a laser diode(LD), and a display unit including the same.

BACKGROUND ART

In recent years, projectors that project an image on a screen have beenwidely used not only in offices but also at home. The projectors eachmodulate light from a light source by a light valve to generate imagelight, and thereafter project the image light on a screen to performdisplay (refer to PTL 1, for example). Recently, the projectors havebeen increasingly downsized, and palm-sized projectors, mobile phoneswith built-in projectors, and other projectors have started to bewidespread.

CITATION LIST Patent Literature

PTL 1: Japanese Unexamined Patent Application Publication No.2008-134324

SUMMARY OF THE INVENTION

Incidentally, it is desirable that the above-described projectors andillumination devices used for the projectors have high uniformity ofilluminance such as brightness and colors on an irradiated surface.Accordingly, in general, an integrator such as a fly-eye lens is used toreduce luminance non-uniformity of illumination light (to uniformizeluminance of illumination light). However, even though the integrator isused, it may not be possible to reduce luminance non-uniformity ofillumination light (it may not be possible to uniformize a luminancedistribution); therefore, further improvement is desired.

It is therefore desirable to provide an illumination device that makesit possible to reduce luminance non-uniformity of illumination light,and a display unit using such an illumination device.

A first illumination device according to an embodiment of the presentdisclosure includes: a light source; and a uniform illumination opticalsystem including a first fly-eye lens that includes a plurality oflenses two-dimensionally arranged and allows light based on emittedlight from the light source to pass through the first fly-eye lens.Light entering the first fly-eye lens has directivity. A first referencedirection in a planar shape of an illumination target region extendsalong a direction substantially parallel to a long-axis direction or ashort-axis direction of an intensity distribution shape of the lightentering the first fly-eye lens, and a periodic direction of an array ofthe lenses in the first fly-eye lens is inclined with respect to thelong-axis direction or the short-axis direction.

A display unit according to an embodiment of the present disclosureincludes an illumination optical system, a light valve, and a projectionlens. The light valve modulates illumination light from the illuminationoptical system on the basis of an image signal to emit thethus-modulated light. The projection lens projects the light from thelight valve toward a projection surface. The illumination optical systemincludes: a light source; and a uniform illumination optical systemincluding a first fly-eye lens that includes a plurality of lensestwo-dimensionally arranged and allows light based on emitted light fromthe light source to pass through the first fly-eye lens. Light enteringthe first fly-eye lens has directivity. A first reference direction in aplanar shape of an illumination target region extends along a directionsubstantially parallel to a long-axis direction or a short-axisdirection of an intensity distribution shape of the light entering thefirst fly-eye lens, and a periodic direction of an array of the lensesin the first fly-eye lens is inclined with respect to the long-axisdirection or the short-axis direction.

In the first illumination device and the display unit according to therespective embodiments of the present disclosure, the light based on theemitted light from the light source passes through the uniformillumination optical system including the first fly-eye lens, andthereafter the light illuminates the illumination target region. Herein,the first reference direction in the planar shape of the illuminationtarget region extends in the direction substantially parallel to thelong-axis direction or the short-axis direction of the intensitydistribution shape of the light entering the first fly-eye lens. Theperiodic direction of the array of the lenses in the first fly-eye lensis inclined with respect to the long-axis direction or the short-axisdirection, which makes it possible to reduce non-uniformity of anintensity distribution in an illumination image after passing throughthe first fly-eye lens.

A second illumination device according to an embodiment of the presentdisclosure includes: a light source; and a uniform illumination opticalsystem including a first fly-eye lens that includes a plurality oflenses two-dimensionally arranged and allows light based on emittedlight from the light source to pass through the first fly-eye lens.Light entering the first fly-eye lens has directivity. The first fly-eyelens has an outer shape reference linearly extending along one directionin a portion of its outer edge, and is disposed to allow a periodicdirection of an array of the lenses to be inclined with respect to anextending direction of the outer shape reference and to allow theextending direction of the outer shape reference to be substantiallyparallel to a long-axis direction or a short-axis direction of anintensity distribution shape of the light entering the first fly-eyelens.

A third illumination device according to an embodiment of the presentdisclosure includes: a light source; and a uniform illumination opticalsystem including a first fly-eye lens that includes a plurality oflenses two-dimensionally arranged and allows light based on emittedlight from the light source to pass through the first fly-eye lens.Light entering the first fly-eye lens has directivity. The first fly-eyelens has an outer shape reference linearly extending along one directionin a portion of its outer edge, and is disposed to allow a periodicdirection of an array of the lenses to be substantially parallel orsubstantially orthogonal to an extending direction of the outer shapereference and to allow the extending direction of the outer shapereference to be inclined with respect to a long-axis direction or ashort-axis direction of an intensity distribution shape of the lightentering the first fly-eye lens.

A fourth illumination device according to an embodiment of the presentdisclosure includes: a light source; a uniform illumination opticalsystem including a first fly-eye lens that includes a plurality oflenses two-dimensionally arranged and allows light based on emittedlight from the light source to pass through the first fly-eye lens; anda housing that is allowed to contain the light source and the firstfly-eye lens. Light entering the first fly-eye lens has directivity, anda periodic direction of an array of the lenses in the first fly-eye lensis inclined with respect to a mounting surface of the housing.

In the first to fourth illumination devices and the display unitaccording to the respective embodiments of the present disclosure, theperiodic direction of the array of the lenses in the first fly-eye lensis inclined with respect to a predetermined direction, which makes itpossible to reduce non-uniformity of the intensity distribution in theillumination image based on the light having directivity. This makes itpossible to reduce luminance non-uniformity of illumination light.

It is to be noted that the above-described contents are examples of thepresent disclosure. Effects of the present disclosure are not limited toeffects described here, and may be other effects or may further includeother effects.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a configuration diagram illustrating an overall configurationof a display unit according to a first embodiment of the presentdisclosure.

FIG. 2A is a cross-sectional view of an example of a configuration ofeach of a red laser, a green laser, and a blue laser illustrated in FIG.1.

FIG. 2B is a cross-sectional view of an example of the configuration ofeach of the red laser, the green laser, and the blue laser illustratedin FIG. 1.

FIG. 3A is a cross-sectional view of another example of theconfiguration of each of the red laser, the green laser, and the bluelaser illustrated in FIG. 1.

FIG. 3B is a cross-sectional view of another example of theconfiguration of each of the red laser, the green laser, and the bluelaser illustrated in FIG. 1.

FIG. 3C is a cross-sectional view of another example of theconfiguration of each of the red laser, the green laser, and the bluelaser illustrated in FIG. 1.

FIG. 4 is a schematic X-Y plan view of a configuration of a firstfly-eye lens illustrated in FIG. 1.

FIG. 5 is a schematic view of an example of disposition of the firstfly-eye lens illustrated in FIG. 4.

FIG. 6 is a schematic view for description of a periodic direction of anarray of lenses in the first fly-eye lens.

FIG. 7 is a main-part configuration diagram for description ofdisposition of a light source section, the first fly-eye lens, and anillumination target region.

FIG. 8 is a schematic X-Y plan view of an intensity (luminance)distribution shape of light entering the first fly-eye lens.

FIG. 9 is a schematic X-Y plan view of a first fly-eye lens according toa comparative example 1 and an intensity distribution shape of enteringlight.

FIG. 10 is a schematic view for description of an intensity distributionshape after passing through the first fly-eye lens illustrated in FIG.9.

FIG. 11A is a schematic view of an illumination image of the comparativeexample 1.

FIG. 11B is a characteristic diagram illustrating an intensitydistribution taken along a line I-I illustrated in FIG. 11A.

FIG. 12 is a schematic X-Y plan view of a first fly-eye lens accordingto a comparative example 2 and an intensity distribution shape ofentering light.

FIG. 13 is a schematic view for description of an intensity distributionshape after passing through the first fly-eye lens illustrated in FIG.12.

FIG. 14A is a schematic view of an illumination image of the comparativeexample 2.

FIG. 14B is a characteristic diagram illustrating an intensitydistribution taken along a line II-II illustrated in FIG. 14A.

FIG. 15 is a schematic view for description of an intensity distributionshape after passing through the first fly-eye lens illustrated in FIG.4.

FIG. 16A is a schematic view of an illumination image illustrated inFIG. 15.

FIG. 16B is a characteristic diagram illustrating an intensitydistribution taken along a line III-III illustrated in FIG. 16A.

FIG. 17 is a schematic X-Y plan view of a first fly-eye lens accordingto a comparative example 3 and an intensity distribution shape ofentering light.

FIG. 18A is a schematic view for description of workings by theintensity distribution shape illustrated in FIG. 17.

FIG. 18B is a schematic view for description of workings and effects bythe intensity distribution shape illustrated in FIG. 8.

FIG. 19A is a schematic view for description of an effective diameter ofan optical component in a case in which the intensity distribution shapeillustrated in FIG. 17 is formed.

FIG. 19B is a schematic view for description of an effective diameter ofan optical component in a case in which the intensity distribution shapeillustrated in FIG. 8 is formed.

FIG. 20 is a schematic X-Y plan view of a configuration of a firstfly-eye lens according to a comparative example 4.

FIG. 21 is a schematic plan view of a configuration of a first fly-eyelens according to a second embodiment of the present disclosure.

FIG. 22 is a schematic X-Y plan view of the first fly-eye lensillustrated in FIG. 21 and an intensity distribution shape of enteringlight.

FIG. 23 is a schematic X-Y plan view of a first fly-eye lens accordingto a modification example 1 and an intensity distribution shape ofentering light.

FIG. 24 is a schematic X-Y plan view of a first fly-eye lens accordingto a modification example 2 and an intensity distribution shape ofentering light.

FIG. 25 is a schematic view for description of an intensity distributionshape after passing through the first fly-eye lens illustrated in FIG.24.

MODES FOR CARRYING OUT THE INVENTION

Some embodiments of the present disclosure are described below in detailwith reference to the drawings. It is to be noted that description isgiven in the following order.

1. First Embodiment (An example of a projection display unit that isconfigured so as to allow a lens array of a fly-eye lens to be inclinedfrom a predetermined direction)

2. Second Embodiment (Another example of inclined disposition of thefly-eye lens)

3. Modification Example 1 (An example in which the fly-eye lens isdisposed with respect to a vertical surface)

4. Modification Example 2 (An example in which a shape of each lens ofthe fly-eye lens is a rectangular shape)

First Embodiment

[Configuration]

FIG. 1 illustrates an example of an overall configuration of a displayunit (a display unit) according to a first embodiment of the presentdisclosure. A display unit 1 may be, for example, a projector thatprojects an image in a magnified form onto, for example, a wall or ascreen.

The display unit 1 may include, for example, an illumination opticalsystem 10, a light valve 21, a polarizing beam splitter 23 serving as apolarization splitting element, a projection lens 24, and anillumination controller 29. It is to be noted that in the followingdescription, a direction along an optical axis Z1 is denoted as a Zdirection (a Z-axis direction), and a horizontal direction and avertical direction in a plane orthogonal to the Z direction arerespectively denoted as an X direction (an X-axis direction) and a Ydirection (a Y-axis direction).

The illumination optical system 10 emits illumination light L1 toilluminate any given region (an illumination target region Sa to bedescribed later). In the present embodiment, the illumination opticalsystem 10 emits the illumination light L1 toward the polarizing beamsplitter 23 to illuminate an effective region serving as theillumination target region Sa of the light valve 21. The illuminationoptical system 10 may include, as a light source section 11, forexample, a blue laser 11B, a green laser 11G, a red laser 11R, a firstcoupling lens 12B, a second coupling lens 12G, a third coupling lens12R, a first dichroic mirror 131, and a second dichroic mirror 132. Theillumination optical system 10 may further include a drive opticalelement 14, a mirror 18, a first fly-eye lens 151, a second fly-eye lens152, a first condenser lens 161, a second condenser lens 162, a thirdcondenser lens 163, and a fourth condenser lens 164. The illuminationoptical system 10 corresponds to a specific example of an “illuminationdevice” of the present disclosure.

The blue laser 11B may be, for example, a laser light source that emitsblue laser light of a wavelength of about 450 nm. The green laser 11Gmay be, for example, a laser light source that emits green laser lightof a wavelength of about 520 nm. The red laser 11R may be, for example,a laser light source that emits red laser light of a wavelength of about640 nm. It is to be noted that a laser diode (LD) is adopted as anon-limiting example of the light source; however, for example, any ofother solid-state light-emitting elements such as a light-emitting diode(LED) and an organic light-emitting diode (OLED) may be used, or acombination of two or more kinds of the solid-state light-emittingelements may be used. Emitted light from the blue laser 11B, the greenlaser 11G, and the red laser 11R has directivity, and a shape of anintensity distribution (an intensity distribution in a plane orthogonalto an optical axis; hereinafter simply referred to as “intensitydistribution”) of the emitted light is anisotropic. In the following, acase in which a laser light source is used for the light source section11 and the shape of the intensity distribution of the emitted light,i.e., a shape of a so-called far-field pattern (FFP) is an ellipsoidalshape is described as an example. Note that technology contents to bedescribed below are applicable widely to a light source that emits lighthaving slight directivity (light that is not isotropic). Examples of thelight source may include a light source using an LED or an LD, and aphosphor that is to be excited by emitted light from the LED or the LD,and a light source using a high-order harmonic by a nonlinear opticalcrystal. The shape of the intensity distribution of the emitted light isnot limited to the ellipsoidal shape, and may be any other shape such asa shape having a relatively long axis direction and a relatively shortaxis direction (a shape that is not isotropic). Moreover, light emittedfrom the light source itself may not have directivity (may have anisotropic intensity distribution). It is because when the light emittedfrom the light source passes through any other optical member (forexample, an anamorphic lens and a diffractive element) disposed betweenthe light source and the uniform illumination optical system, theintensity distribution may become anisotropic. In other words, contentsof the present disclosure are effective in a case in which an intensitydistribution of light entering a fly-eye lens (herein, the first fly-eyelens 151) of a uniform illumination optical system has directivity, andthe kind of the light source is not limited. However, the contents arespecifically effective in a case using a light source that emits light,such as laser light, having different intensity distributions along twoaxis directions orthogonal to each other, and have a great merit inuniformization.

FIGS. 2A and 2B each illustrate an example of each of configurations ofthe blue laser 11B, the green laser 11G, and the red laser 11R. The bluelaser 11B, the green laser 11G, and the red laser 11R each may include aplurality of chips 112A.

The chips 112A each may be configured of, for example, an edge-emittinglaser diode that emits light of a predetermined wavelength, and may havea single light-emitting spot 112B. Wavelengths of light emitted from theplurality of chips 112A may be the same as or different from oneanother. For example, the plurality of chips 112A may be disposed alongthe X direction in an inner space enclosed with a stem 113 and a cap114. The number of the chips 112A may be different in each of the bluelaser 11B, the green laser 11G, and the red laser 11R, or may be thesame in all of the blue laser 11B, the green laser 11G, and the redlaser 11R.

The stem 113 may enclose the chips 112A together with the cap 114, andmay include, for example, a supporting substrate 113A that supports asubmount 115, an outer frame substrate 113B disposed on a back surfaceof the supporting substrate 113A, and a plurality of connectionterminals 113C.

The submount 115 may be made of a material having conductivity andthermal dissipation. Each of the supporting substrate 113A and the outerframe substrate 113B may be configured of a base having conductivity andheat dissipation in which one or more insulating through holes and oneor more conductive through holes are formed. The supporting substrate113A and the outer frame substrate 113B each may have, for example, adisk shape, and may be stacked so as to allow central axes (notillustrated) thereof to be superimposed on each other. A diameter of theouter frame substrate 113B may be larger than a diameter of thesupporting substrate 113A. An outer edge of the outer frame substrate113B may be a ring-shaped flange hanging over in a radiation directionfrom the central axis of the outer frame substrate 113B in a planehaving a normal along the central axis of the outer frame substrate113B. The flange has a role in determining a reference position when thecap 114 is fit into the supporting substrate 113A in a manufacturingprocess.

At least one terminal (hereinafter referred to as “terminal α” forconvenience sake) of the plurality of connection terminals 13C may beelectrically coupled to an electrode (not illustrated) of each of thechips 112A. For example, one end of the terminal α may protrude longfrom the outer frame substrate 113B, and the other end of the terminal αmay protrude short from the supporting substrate 113A, and may beelectrically coupled to each of the chips 112A through a wire 116.Moreover, terminals (hereinafter referred to as “terminals β” forconvenience sake) other than the terminals α of the plurality ofconnection terminals 113C may be electrically coupled to otherelectrodes (not illustrated) of all of the chips 112A. For example, oneend of each of the terminals β may protrude long from the outer framesubstrate 113B, and the other end of each of the terminals β may beembedded in the supporting substrate 113A and may be electricallycoupled to all of the chips 112A through the supporting substrate 113Aand the submount 115. A portion protruding long from the outer framesubstrate 113 of each of the connection terminals 113C may correspond toa portion fit in, for example, a substrate. The terminals α may besupported by the insulating through holes provided in the supportingsubstrate 113A and the outer frame substrate 113B, and may be insulatedand separated from the supporting substrate 113A and the outer framesubstrate 113B by the through holes. Moreover, the respective terminalsα may be insulated and separated from one another by the above-describedinsulating members. In contrast, the terminals β may be supported by theconductive through holes provided in the supporting substrate 113A andthe outer frame substrate 113B, and may be electrically coupled to thethrough holes.

The cap 114 may have, for example, a cylindrical portion 114A havingopenings in upper and lower ends thereof. The lower end of thecylindrical portion 114A may be in contact with, for example, a sidesurface of the supporting substrate 113A, and the chips 112A may bedisposed in an inner space of the cylindrical portion 114A. The cap 114may have a light transmission window 114B that is disposed so as toblock the opening on the upper end of the cylindrical portion 14A. Thelight transmission window 14B may be disposed so as to face a lightemission surface of each of the plurality of chips 112A, and may have afunction of allowing light outputted from each of the chips 112A to passtherethrough.

FIGS. 3A and 3B each illustrate another example of each of theconfigurations of the blue laser 11B, the green laser 11G, and the redlaser 11R. The blue laser 11B, the green laser 11G, and the red laser11R each may include the plurality of chips 112A as described above, ormay include a single chip 112A. Moreover, one chip 112A may have amonolithic structure as illustrated in FIG. 3C, and in this case, aplurality of (herein, two) light-emitting spots 112B may be formed.

The blue laser 11B, the green laser 11G, and the red laser 11R arearranged so as to allow a long-axis direction and a short-axis directionof an intensity distribution shape (an intensity distribution shape in aplane orthogonal to the optical axis Z1) of emitted light from the lightsource section 11 (light based on emitted light from the blue laser 11B,emitted light from the green laser 11G, and the emitted light from thered laser 11R) to be substantially parallel or substantially orthogonalto the X-axis direction and the Y-axis direction. A case in which along-axis direction (A_(L)) and a short-axis direction (A_(S)) of anintensity distribution shape of the emitted light from the light sourcesection 11 (i.e., light entering the first fly-eye lens 151) aresubstantially parallel to the Y-axis direction and the X-axis direction,respectively, is described as an example below. Conversely, thelong-axis direction (A_(L)) and the short-axis direction (A_(S)) may besubstantially parallel to the X-axis direction and the Y-axis direction,respectively.

The illumination controller 29 may perform light emission control of theblue laser 11B, the green laser 11G, and the red laser 11R, for example.The illumination controller 29 may perform light emission control ofeach of the blue laser 11B, the green laser 11G, and the red laser 11Rby a field sequential system.

The second coupling lens 12G may be a lens (a coupling lens) adapted tocollimate green laser light emitted from the green laser 11G (intoparallel light) to couple the thus-collimated green laser light to thefirst dichroic mirror 131. Similarly, the first coupling lens 12B may bea lens (a coupling lens) adapted to collimate blue laser light emittedfrom the blue laser 11B to couple the thus-collimated blue laser lightto the first dichroic mirror 131. Moreover, the third coupling lens 12Rmay be a lens adapted to collimate red laser light emitted from the redlaser 11R to couple the thus-collimated red laser light to the seconddichroic mirror 132. It is to be noted that the coupling lenses 12R,12G, and 12B may preferably collimate respective entering laser light(into parallel light).

The dichroic mirror 131 may be a mirror that selectively allows the bluelaser light entering the dichroic mirror 131 through the first couplinglens 12B to pass therethrough and selectively reflects the green laserlight entering the dichroic mirror 131 through the second coupling lens12G. The dichroic mirror 132 may be a mirror that selectively allows theblue laser light and the green laser light outputted from the firstdichroic mirror 131 to pass therethrough and selectively reflects thered laser light entering the dichroic mirror 132 through the thirdcoupling lens 12R. Thus, color synthesis (optical path synthesis) of thered laser light, the green laser light, and the blue laser light isperformed.

The drive optical element 14 may be an optical element adapted to reducespeckle noise and interference fringes in the illumination light L1, andmay be disposed in an optical path between the first condenser lens 161and the second condenser lens 162. The drive optical element 14 mayminutely vibrate, for example, in a direction along the optical axis ora direction orthogonal to the optical axis to change a state of a lightflux passing therethrough, which makes it possible to reduce specklenoise and interference fringes in the illumination light L1.

Each in the first fly-eye lens 151 and the second fly-eye lens 152 maybe an optical member (an integrator) configured of a plurality of lensesthat are two-dimensionally arranged on a substrate, and may spatiallydivide an entering light flux into a plurality of light fluxes inaccordance with an array of the lenses to superimpose the light fluxesentering the respective lenses on one another and emit thethus-superimposed light fluxes. The first fly-eye lens 151 may bedisposed in an optical path between the second dichroic mirror 132 andthe first condenser lens 161. The second fly-eye lens 152 may bedisposed in an optical path between the second condenser lens 162 andthe third condenser lens 163. The first fly-eye lens 151 and the secondfly-eye lens 152 may uniformize a light amount distribution in a planeof the illumination light. In each of the first fly-eye lens 151 and thesecond fly-eye lens 152, a plurality of lenses (a lens array) may beformed on both surfaces on light entry side and light exit side.Alternatively, the first fly-eye lens 151 and the second fly-eye lens152 each may be configured of a plurality of lenses formed on one of thesurfaces on the light entry side and the light exit side.

The first fly-eye lens 151 and the second fly-eye lens 152 correspond tospecific examples of a “uniform illumination optical system” of thepresent disclosure. In the present embodiment, as described in detaillater, the first fly-eye lens 151 disposed on the light source side ofthese fly-eye lenses is disposed so as to allow a periodic direction ofa lens array to be inclined at a predetermined angle.

The mirror 18 may be disposed in an optical path between the firstcondenser lens 161 and the drive optical element 14. The first condenserlens 161 may be a lens adapted to condense light exiting from the firstfly-eye lens 151 and allow the thus-condensed light to enter the driveoptical element 14 through the mirror 18. The second condenser lens 162may be a lens adapted to condense light exiting from the drive opticalelement 14 and allow the thus-condensed light to enter the secondfly-eye lens 152.

The third condenser lens 163 and the fourth condenser lens 164 each maybe a lens adapted to condense light exiting from the second fly-eye lens152 and output the thus-condensed light as the illumination light L1.

The polarization beam splitter 23 may be configured of a plurality ofprisms that are bonded together and each have respective surfaces coatedwith an optical functional film, and may be a polarization splittingelement that separates light having entered the polarization splittingelement into a first polarized component (for example, an S-polarizedcomponent) and a second polarized component (for example, a P-polarizedcomponent) and outputs the first polarized component and the secondpolarized component to different directions. The polarizing beamsplitter 23 may selectively reflect, for example, the S-polarizedcomponent and may selectively allow, for example, the P-polarizedcomponent to pass therethrough. It is to be noted that any otherpolarization splitting element, for example, a wire grid or apolarization film may be used in place of the polarizing beam splitter23.

The polarizing beam splitter 23 may reflect, for example, almost theentirety of the S-polarized component of the illumination light L1having entered the polarizing beam splitter 23 to output thethus-reflected S-polarized component toward the light valve 21. TheS-polarized component may be modulated (rotated) by the light valve 21into modulated light of a P-polarized component to enter the polarizingbeam splitter 23 again. The P-polarized component may pass through thepolarizing beam splitter 23, and thereafter may be projected onto aprojection surface 30A of a screen 30 through the projection lens 24.

The light valve 21 may be a reflective liquid crystal element such as aLCOS (Liquid Crystal On Silicon). The light valve 21 may modulate thefirst polarized component (for example, the S-polarized component)included in the illumination light L1 having entered the light valve 21through the polarizing beam splitter 23 on the basis of an image signal.The light valve 21 may output the thus-modulated light toward theprojection lens 24 through the polarizing beam splitter 23. The lightvalve 21 may output modulated light of which a polarization state isrotated from a polarization state of light entering the light valve 21.It is to be noted that the light valve 21 may return the S-polarizedcomponent entering the light valve 21 without changing its polarizationstate, which makes it possible to perform black display. A firstreference direction in an effective region (the illumination targetregion Sa) of the light valve 21 extends along a direction substantiallyparallel to the X-axis direction or the Y-axis direction. Herein, aplanar shape of the effective region of the light valve 21 is arectangular shape, and the first reference direction is a directionalong a side of the rectangular shape. More specifically, a long sideand a short side of the rectangular shape are substantially parallel tothe X-axis direction and the Y-axis direction, respectively.

The projection lens 24 may project the modulated light having enteredfrom the light valve 21 through the polarizing beam splitter 23 onto theprojection surface 30A of the screen 30.

(Configuration and Disposition of First Fly-Eye Lens)

FIG. 4 illustrates an X-Y planar configuration of the first fly-eye lens151. In the first fly-eye lens 151, a plurality of lenses 151 a aretwo-dimensionally arranged on at least one surface (for example, a lightentry surface) as illustrated in the drawing. A planar shape (an X-Yplanar shape) of each of the lenses 151 a may be, for example, a regularhexagonal shape. The regular hexagonal lenses 151 a may be laid on anX-Y plane, i.e., may be arranged in a honeycomb fashion as a whole. Sucharrangement enhances an effect of superimposing entering light fluxesand facilitates uniformization of a luminance distribution of lightentering the second fly-eye lens 152. However, the planar shape of eachof the lenses 151 a is not limited to such a regular hexagonal shape,and may be any other shape, for example, a square shape, a rectangularshape (to be described later), or a regular triangular shape. It is tobe noted that the number and array of the lenses 151 a illustrated inFIG. 4 are simplified for description, and are not limited to thoseillustrated in the drawing, and may be different from those illustratedin the drawing.

In such a first fly-eye lens 151, a periodic direction A1 of the arrayof the lenses 151 a is inclined with respect to the X-axis direction orthe Y-axis direction (for example, may be inclined at an inclinationangle θ₁₁ with respect to the X-axis direction). Herein, the X-axisdirection and the Y-axis direction are coincident with the long-axisdirection (A_(L)) and the short-axis direction (A_(S)) of the intensitydistribution shape (a light source image) of emitted light from the bluelaser 11B, the green laser 11G, and the red laser 11R. Moreover, theplanar shape of the effective region serving as the illumination targetregion Sa of the light valve 21 may be a planar shape (herein, arectangular shape) having sides (herein, a short side and a long side)extending along a direction (the first reference direction)substantially parallel to the long-axis direction A_(L) or theshort-axis direction A_(S).

The first fly-eye lens 151 may have a linearly extending reference (anouter shape reference P_(STD)) in a portion of its outer edge. In thepresent embodiment, in a plane orthogonal to the optical axis Z1, theplurality of lenses 151 a are formed so as to allow the periodicdirection A1 to be inclined at a predetermined angle (the inclinationangle θ₁₁) with respect to an extending direction of the outer shapereference P_(STD). Herein, the extending direction of the outer shapereference P_(STD) is substantially parallel to the short-axis directionA_(S) (the X-axis direction). For example, the first fly-eye lens 151may be held so as to dispose the outer shape reference P_(STD) along aholding member 17, as illustrated in FIG. 5. The first fly-eye lens 151may be contained in a housing 18 while being held by the holding member17. In other words, the periodic direction A1 of the lenses 151 a in thefirst fly-eye lens 151 may be inclined with respect to a mountingsurface 18 _(a) of the housing 18. The holding member 17 may hold thefirst fly-eye lens 151 only, or may be allowed to hold a plurality ofoptical components including the first fly-eye lens 151 that arearranged along an optical axis direction.

In the following, description is given of the periodic direction A1 ofthe lenses 151 a. The periodic direction A1 of the array of the lenses151 a is denoted as a direction where an interval between adjacentlenses 151 a is minimum. In a case in which the planar shape of each ofthe lenses 151 a is a regular hexagonal shape, three periodic directionsA11, A12, and A13 in total are present, as illustrated in FIG. 6. In acase in which a plurality of periodic directions are present in such amanner, a periodic direction forming a minimum angle with the X-axisdirection (the short-axis direction A_(S)) or the Y-axis direction (thelong-axis direction A_(L)) is denoted as the “periodic direction A1”.Herein, for example, θ₁₁≤θ₁₂≤θ₁₃ may be established, and the periodicdirection A11 forming the minimum angle with the X-axis direction out ofthe periodic directions A11, A12, and A13 may be set as the periodicdirection A1.

FIG. 7 illustrates a disposition example in the display unit 1. However,in FIG. 7, only a main part of the display unit 1 is illustrated, andsome optical components are omitted for simplification. The light sourcesection 11, the first fly-eye lens 151, and the light valve 21 servingas an illumination target may be disposed along the optical axis Z1 asillustrated in the drawing.

Light based on emitted light (combined light) from the blue laser 11B,the green laser 11G, and the red laser 11R may show, for example, anellipsoidal intensity (luminance) distribution shape SL₁ (may form anellipsoidal far field pattern (FFP)) on the light entry surface in thefirst fly-eye lens 151. For example, the short-axis direction A_(S) andthe long-axis direction A_(L) of the intensity distribution shape SL₁may be substantially parallel to the X-axis direction and the Y-axisdirection, respectively. More specifically, the blue laser 11B, thegreen laser 11G, and the red laser 11R may be disposed on the opticalaxis so as to allow the short-axis direction A_(S) and the long-axisdirection A_(L) of the intensity distribution shape SL₁ to besubstantially parallel to the X-axis direction and the Y-axis direction,respectively.

In contrast, the light valve 21 may have a rectangular effective regionas the illumination target region Sa. The light valve 21 may be disposedon the optical axis so as to allow a long side and a short side of therectangular shape of the effective region to be substantially parallelto the X-axis direction and the Y-axis direction, respectively.

Meanwhile, the first fly-eye lens 151 may be disposed so as to allow theperiodic direction A1 of the array of the lenses 151 a to be inclinedwith respect to the short-axis direction A_(S) (the X-axis direction),as described above. In the present embodiment, the long-axis directionA_(L) and the short-axis direction A_(S) of the intensity distributionshape SL₁ of the emitted light from the light source section 11 (thelight entering the first fly-eye lens 151) are substantially parallel tothe short side and the long side of the illumination target region Sa insuch a manner. In contrast, the periodic direction A1 in the firstfly-eye lens 151 may be inclined with respect to the long-axis directionA_(L) or the short-axis direction A_(S). More specifically, out of thelight source section 11, the first fly-eye lens 151, and the light valve21, only a two-dimensional array of the lenses 151 a in the firstfly-eye lens 151 may be rotated about the optical axis Z1 by apredetermined angle (the inclination angle θ₁₁).

Herein, in a case in which the planar shape of each of the lenses 151 ais a regular hexagonal shape, the inclination angle θ₁₁ may bedesirably, for example, greater than 0 degrees and smaller than 30degrees, and more specifically 15 degrees. In a case in which theinclination angle θ₁₁ is 15 degrees, it is possible to maximize a lightsuperimposition effect (superimposing effect) by the first fly-eye lens151, thereby effectively reducing non-uniformity of an in-planeintensity distribution (in-plane illuminance distribution) in theillumination light L1.

[Workings and Effects]

In the display unit 1, the in-plane intensity distribution of theemitted light (laser light) from the light source section 11 isuniformized by the uniform illumination optical system (the firstfly-eye lens 151 and the second fly-eye lens 152), and the emitted lightis outputted as the illumination light L1 from the illumination opticalsystem 10. A portion (for example, the S-polarized component) of theillumination light L1 enters the light valve 21 through the polarizingbeam splitter 23, and is modulated by the light valve 21 on the basis ofan image signal inputted from an external device. The thus-modulatedlight is outputted as, for example, the P-polarized component from thelight valve 21, and thereafter enters the projection lens 24 through thepolarizing beam splitter 23. Thus, an image is displayed on theprojection surface 30A of the screen 30 by the projection lens 24. Inthe display unit 1, an image is displayed in such a manner.

Herein, in the present embodiment, it is characterized that the periodicdirection A1 of the lenses 151 a in the first fly-eye lens 151 isinclined with respect to the long-axis direction A_(S) or the short-axisdirection A_(S). More specifically, the first fly-eye lens 151 isconfigured so as to allow the periodic direction A1 of the lenses 151 ato be inclined with respect to the extending direction of the outershape reference P_(STD). In contrast, the long-axis direction A_(L) andthe short-axis direction A_(S) of the intensity distribution shape SL₁of the light entering the first fly-eye lens 151 are substantiallyparallel to the short side and the long side of the rectangular shape ofthe light valve 21. Accordingly, the intensity distribution shape SL₁formed on the light entry surface of the first fly-eye lens 151 isformed over a plurality of selective lenses 151 a (lenses 151 a 1, 151 a2, 151 a 3, 151 a 4, and 151 a 5), as illustrated in FIG. 8.

COMPARATIVE EXAMPLES

FIG. 9 schematically illustrates a configuration example of a firstfly-eye lens according to a comparative example 1 of the presentembodiment together with the intensity distribution shape SL₁. In thecomparative example 1, unlike the present embodiment, a periodicdirection A100 of an array of lenses 151 b in the first fly-eye lens issubstantially parallel to the long-axis direction A_(L) of the intensitydistribution shape SL₁. In other words, an inclination angle of theperiodic direction A100 with respect to the long-axis direction A_(L) ofthe intensity distribution shape SL₁ is 0 degrees. It is to be notedthat an inclination angle of the periodic direction A100 with respect tothe short-axis direction A_(S) is 30 degrees.

In the first fly-eye lens of the comparative example 1, the intensitydistribution shape SL₁ is formed over a plurality of selected lenses 151b (lenses 151 b 1 to 151 b 5). Accordingly, as schematically illustratedin FIG. 10, an intensity distribution shape (an illumination imageSL₁₀₀) of light having passed through the first fly-eye lens correspondsto superimposition of light fluxes having entered the respective lenses151 b 1 to 151 b 5. As a result, in the comparative example 1, anintensity distribution in the illumination image SL₁₀₀ is biased to alocal portion (for example, a portion around a center) in a plane.Moreover, as can be seen from a cross-section taken along an arrow lineI-I of FIG. 11A, the illumination image SL₁₀₀ has a non-uniformdistribution as illustrated in FIG. 11B. Accordingly, in a case in whichthe inclination angle with respect to the long-axis direction A_(L) ofthe intensity distribution shape SL₁ is 0 degrees, a superimpositioneffect by the first fly-eye lens is not sufficient.

FIG. 12 schematically illustrates a first fly-eye lens according to acomparative example 2 of the present embodiment together with theintensity distribution shape SL₁. In the comparative example 2, unlikethe present embodiment, a periodic direction A101 of an array of lenses151 c in the first fly-eye lens is substantially parallel to theshort-axis direction A_(S) of the intensity distribution shape SL₁. Inother words, an inclination angle of the periodic direction A101 withrespect to the short-axis direction A_(S) of the intensity distributionshape SL₁ is 0 degrees (an inclination angle of the periodic directionA101 with respect to the long-axis direction A_(L) is 30 degrees).

In the first fly-eye lens of the comparative example 2, the intensitydistribution shape SL₁ is formed over a plurality of selected lenses 151c (lenses 151 c 1 to 151 c 7). Accordingly, as schematically illustratedin FIG. 13, an intensity distribution shape (an illumination imageSL₁₀₁) of light having passed through the first fly-eye lens correspondsto superimposition of light fluxes having entered the respective lenses151 c 1 to 151 c 7. As a result, in the comparative example 2, anintensity distribution in the illumination image SL₁₀₁ is biased to alocal portion in a plane. Moreover, as can be seen from a cross-sectiontaken along an arrow line II-II of FIG. 14A, the illumination imageSL₁₀₁ has a non-uniform distribution as illustrated in FIG. 14B.Accordingly, even in a case in which the inclination angle with respectto the short-axis direction A_(S) of the intensity distribution shapeSL₁ is 0 degrees, a superimposition effect by the first fly-eye lens isnot sufficient.

In contrast, in the present embodiment, as schematically illustrated inFIG. 15, an intensity distribution shape (an illumination image SL₂) oflight having passed through the first fly-eye lens 151 corresponds tosuperimposition of light fluxes having entered the respective lenses 151a 1 to 151 a 5 in FIG. 8. As a result, in the present embodiment, unlikethe comparative examples 1 and 2, an intensity distribution in theillumination image SL₂ is less likely to be biased, thereby reducingintensity non-uniformity (illuminance non-uniformity). Moreover, as canbe seen from a cross-section taken along an arrow line III-III of FIG.16A, the illumination image SL₂ has a substantially uniform distributionas illustrated in FIG. 16B. It is to be noted that this distribution isa distribution in a case in which the inclination angle θ₁₁ is 15degrees.

As described above, inclining the periodic direction A1 of the lenses151 a in the first fly-eye lens 151 from a predetermined direction makesit possible to reduce non-uniformity of the intensity distribution inthe illumination light L1 even in a case in which the emitted light fromthe light source section 11 is light having directivity, for example,laser light.

(Merits by Inclined Disposition of Lens)

Here, FIG. 17 illustrates, as a comparative example 3 of the presentembodiment, an X-Y planar configuration of a first fly-eye lens 100 andan intensity distribution shape SL₃ of emitted light from the lightsource section 11 (light entering the first fly-eye lens 100). Asillustrated in the drawing, in the comparative example 3, while aperiodic direction A102 of an array of lenses 100 a in the first fly-eyelens 100 is substantially parallel to the X-axis direction, thelong-axis direction A_(L) and the short-axis direction A_(S) of theintensity distribution shape SL₃ are inclined from the X-axis directionand the Y-axis direction. Such disposition in this comparative exampleis achievable by disposing respective laser light sources (the bluelaser 11B, the green laser 11G, and the red laser 11R) in the lightsource section 11 in a state in which the respective laser sources arerotated around the optical axis. Even in the comparative example 3, asuperimposition effect similar to that in the present embodiment isachievable. In other words, when the periodic direction of a lens arrayis relatively inclined with respect to the long-axis direction or theshort-axis direction of the intensity distribution shape of lightentering the first fly-eye lens, the above-described superimpositioneffect is achievable, thereby allowing for reduction in non-uniformityof the intensity distribution in the illumination image.

However, in a case in which the respective laser sources of the lightsource section 11 are disposed so as to be rotated around the opticalaxis, for example, as illustrated in FIG. 18A, a polarization directionL_(DP) of each of the laser light sources in the intensity distributionshape SL₃ may not be coincident with, for example, the S-polarizedcomponent, and reflected light (the S-polarized component) by thepolarizing beam splitter 23 may be slightly mixed with the P-polarizedcomponent. Namely, a ratio of polarized light entering the polarizingbeam splitter 23 is worsened. As a result, a contrast ratio in displayimage quality declines.

In contrast, in a case in which the periodic direction A1 of the lenses151 a in the first fly-eye lens 151 is inclined without changing thepositions of the respective laser light sources of the light sourcesection 11 as with the present embodiment, for example, as illustratedin FIG. 18B, in the intensity distribution shape SL₁, the polarizationdirection L_(DP) of each of the laser light sources may be coincidentwith, for example, the S-polarized component, and the P-polarizedcomponent may be less likely to enter the polarization beam splitter 23.Namely, a ratio of polarized light entering the polarizing beam splitter23 is improved, which makes it possible to achieve a favorable contrastratio in display image quality.

Moreover, in the above-described comparative example 3, the laser lightsources themselves are rotated, and the intensity distribution shape SL₃of emitted light from the light source section 11 is inclined from theX-axis direction and the Y-axis direction; therefore, for example, anoptical effective region (an effective diameter) E100 for securing of aprojection area of the intensity distribution shape SL₃ may tend tobecome relatively large, as illustrated in FIG. 19A. As a result, a sizeof an optical component (for example, an optical path synthesizingcomponent) is increased.

In contrast, in the present embodiment, owing to inclined disposition ofthe lenses 151 a, it is not necessary to rotate the laser light sourcesthemselves. Accordingly, for example, an optical effective region (aneffective diameter) E1 for securing of a projection area of theintensity distribution shape SL₁ may become relatively small, asillustrated in FIG. 19B. As a result, it is possible to reduce the sizeof the optical component (for example, the optical synthesizingcomponent), which is advantageous in size reduction in an opticalsystem.

It is to be noted that, in order to achieve the above-describedsuperimposition effect, for example, a first fly-eye lens 101 of acomparative example 4 illustrated in FIG. 20 may be used. In the firstfly-eye lens 101, the positions of lenses 101 a are shifted on arow-by-row basis or a column-by-column basis along the Y-axis directionor the X-axis direction (herein, on the column-by-column basis along theY-axis direction). However, it is extremely difficult to manufacture thefirst fly-eye lens 101 having such a lens array. More specifically, itmay be possible to manufacture the first fly-eye lens 101 by, forexample, injection molding, and a mold used for the injection molding ismanufactured as follows. A plurality of (for five columns) molds of alens array corresponding to one column along the Y direction in FIG. 20may be fabricated by, for example, cutting, and thereafter, the moldsfor five columns may be aligned and combined to form a mold for thefirst fly-eye lens 101 having a configuration illustrated in FIG. 20.Therefore, fabrication of the mold involves cost, and it is difficult toachieve accuracy. An alternative technique is forming molds collectively(at a time), but in this case, a planar shape of each of the lenses 101a is not formed in a perfect rectangular shape (an enlarged view of aportion indicated by an alternate long and short dashed line in FIG.20).

As described above, in the present embodiment, the periodic direction A1of the array of the lenses 151 a in the first fly-eye lens 151 isinclined with respect to the long-axis direction A_(L) or the short-axisdirection A_(S) of the intensity distribution shape SL₁, which makes itpossible to reduce non-uniformity of the intensity distribution in theillumination image based on light having directivity. Accordingly, it ispossible to reduce luminance non-uniformity of illumination light.

In the following, description is given of other embodiments of thepresent disclosure and modification examples thereof. It is to be notedthat substantially same components as the components of the foregoingfirst embodiment are denoted by same reference numerals, and anyredundant description thereof is omitted.

Second Embodiment

FIG. 21 illustrates a configuration of a first fly-eye lens (a firstfly-eye lens 153) according to a second embodiment of the presentdisclosure. In the foregoing first embodiment, description has beengiven of a case in which the periodic direction A1 of the lenses 151 ain the first fly-eye lens 151 is inclined with respect to the extendingdirection (the X-axis direction) of the outer shape reference P_(STD);however, it may not be necessary to incline the periodic direction ofthe lenses with respect to the extending direction of the outer shapereference P_(STD). More specifically, as with the first fly-eye lens 153illustrated in FIG. 21, a periodic direction A2 of an array of lenses153 a may be substantially parallel or substantially orthogonal (herein,substantially parallel) to the extending direction of the outer shapereference P_(STD).

Note that, in the present embodiment, unlike the foregoing firstembodiment, for example, the first fly-eye lens 153 may be disposed soas to be inclined at a predetermined angle (an inclination angle θ₂)from the short-axis direction A_(S) (the X-axis direction) by theholding member 17, as illustrated in FIG. 22. It is to be noted that, inthe present embodiment, the configuration and disposition of the firstfly-eye lens 153 is different from those in the foregoing firstembodiment, and configurations and disposition of other opticalcomponents including the light source section 11 and the light valve 21are similar to those in the foregoing first embodiment. In other words,even in the present embodiment, the long-axis direction A_(L) and theshort-axis direction A_(S) of the intensity distribution shape SL₁ oflight entering the first fly-eye lens 153 (emitted light from the lightsource section 11) are coincident with the X-axis direction or theY-axis direction. Moreover, the long-axis direction A_(L) and theshort-axis direction A_(S) are substantially parallel to the short sideand the long side of the effective region serving as the illuminationtarget region Sa of the light valve 21, respectively.

With such disposition, the periodic direction A2 of the lenses 153 a maybe inclined with respect to the long-axis direction A_(L) and theshort-axis direction A_(S). In other words, the periodic direction A2 ofthe lenses 153 a in the first fly-eye lens 153 may be inclined withrespect to the mounting surface 18 _(a) of the housing 18. Moreover, aswith the inclination angle θ₁₁ in the foregoing first embodiment, in acase in which the planar shape of each of the lenses 153 a is a regularhexagonal shape, the inclination angle θ₂ may be desirably, for example,greater than 0 degrees and smaller than 30 degrees, and morespecifically 15 degrees.

In the present embodiment, the periodic direction A2 of the array of thelenses 153 a in the first fly-eye lens 153 is substantially parallel orsubstantially orthogonal to the extending direction of the outer shapereference P_(STD), and the extending direction of the outer shapereference P_(STD) is inclined with respect to the long-axis directionA_(L) or the short-axis direction A_(S) in the intensity distributionshape SL₁. Accordingly, as with the foregoing first embodiment, asuperimposition effect by the first fly-eye lens 153 is effectivelyachieved, which makes it possible to achieve effects similar to those inthe foregoing first embodiment.

Modification Example 1

FIG. 23 is a schematic view of a disposition example of a first fly-eyelens according to a modification example 1. The foregoing firstembodiment involves an example in which the first fly-eye lens 151 isdisposed on a horizontal plane (an X-Z plane) so as to dispose theextending direction of the outer shape reference P_(STD) along theX-axis direction; however, as with the present modification example, thefirst fly-eye lens 151 may be disposed on a vertical plane (a Y-Z plane)so as to dispose the extending direction of the outer shape referenceP_(STD) along the Y-axis direction. Moreover, in the presentmodification example, a periodic direction A3 of the lenses 151 a in thefirst fly-eye lens 151 may be inclined at a predetermined angle (aninclination angle θ₃) with respect to the short-axis direction A_(S)(the X-axis direction), and may be substantially orthogonal to theshort-axis direction A_(S) and the extending direction of the outershape reference P_(STD). As with the inclination angle θ₁₁ in theforegoing first embodiment, in a case in which a planar shape of each ofthe lenses 153 a is a regular hexagonal shape, the inclination angle θ₃may be desirably, for example, greater than 0 degrees and smaller than30 degrees, and more specifically 15 degrees.

Even in the present modification example, the periodic direction A3 inthe first fly-eye lens 151 is inclined with respect to the long-axisdirection A_(L) or the short-axis direction A_(S) of the intensitydistribution shape SL₁, which makes it possible to achieve effectssimilar to those in the foregoing first embodiment.

Modification Example 2

FIG. 24 is a schematic X-Y plan view of a first fly-eye lens (a firstfly-eye lens 154) according to a modification example 2 and an intensitydistribution shape of entering light. As with the foregoing firstembodiment, the first fly-eye lens 154 of the present modificationexample may include a plurality of lenses 154 a that aretwo-dimensionally arranged on at least one surface of a substrate.Moreover, the periodic direction A3 of the lenses 154 a may be inclinedwith respect to the long-axis direction A_(L) or the short-axisdirection A_(S). However, in the present modification example, a planarshape of each of the lenses 154 a is a rectangular shape. Even in thiscase, as schematically illustrated in FIG. 25, it is possible to reduceluminance non-uniformity in an intensity distribution shape SL₃ of lighthaving passed through the first fly-eye lens 154 (after superimposinglight fluxes). As described above, the planar shape of each of thelenses 154 a in the first fly-eye lens 154 may be a rectangular shape.

Although description has been made by giving the embodiments and themodification examples thereof, the present disclosure is not limitedthereto and may be modified in a variety of ways. For example, in theforegoing embodiments and examples, as the first fly-eye lens, a fly-eyelens having a predetermined outer shape reference in its outer edge isexemplified; however, the first fly-eye lens may not have such an outershape reference. As long as the periodic direction of an array of lensesis inclined with respect to the long-axis direction or the short-axisdirection of the intensity distribution shape of emitted light from thelight source section, effects of the present disclosure are achievable.

Moreover, in the foregoing embodiments and examples, as the illuminationtarget region of the illumination optical system (an illuminationdevice), the effective region of the light valve is exemplified;however, the illumination target region is not limited thereto, and anyof various regions may be set as the illumination target region.Further, the planar shape of the illumination target region is notlimited to the above-described rectangular shape. Any shape having aside or an axis (a long axis or a short axis) along a direction (thefirst reference direction) extending along the long-axis direction orthe short-axis direction may be adopted. For example, a square shape orany other polygonal shape may be adopted, or a shape not having astraight line such as an ellipsoidal shape and a circular shape may beadopted.

Furthermore, in the foregoing embodiments and examples, a case in whichthe light valve 21 is configured of a reflective liquid crystal displayelement has been described; however, the light valve 21 is not limitedthereto, and may be configured of, for example, a digital micromirrordevice (DMD).

In addition, in the foregoing embodiments and examples, respectivecomponents (optical systems) of the illumination optical system and thedisplay unit have been specifically described. However, all of thecomponents are not necessarily provided, and other components may befurther provided.

Moreover, in the foregoing embodiments and examples, as application ofthe illumination device of the present disclosure, the display unit suchas the projection display unit has been described as an example;however, the application is not limited thereto, and the illuminationdevice of the present disclosure is applicable to an exposure apparatussuch as a stepper, for example.

It is to be noted that effects described in the foregoing embodimentsand examples are merely exemplified, and effects of the presentdisclosure may be other effects or may further include other effects.

Moreover, the present disclosure may adopt the following configurations.

-   (1)

An illumination device, including:

a light source; and

a uniform illumination optical system including a first fly-eye lensthat includes a plurality of lenses two-dimensionally arranged andallows light based on emitted light from the light source to passthrough the first fly-eye lens, wherein

light entering the first fly-eye lens has directivity,

a first reference direction in a planar shape of an illumination targetregion extends along a direction substantially parallel to a long-axisdirection or a short-axis direction of an intensity distribution shapeof the light entering the first fly-eye lens, and

a periodic direction of an array of the lenses in the first fly-eye lensis inclined with respect to the long-axis direction or the short-axisdirection.

-   (2)

The illumination device according to (1), wherein the first fly-eye lenshas an outer shape reference linearly extending along one direction in aportion of its outer edge.

-   (3)

The illumination device according to (2), wherein the first fly-eye lensis disposed to allow a periodic direction of the lenses to be inclinedwith respect to an extending direction of the outer shape reference andto allow the extending direction of the outer shape reference to besubstantially parallel to the long-axis direction or the short-axisdirection.

-   (4)

The illumination device according to (2), wherein the first fly-eye lensis disposed to allow a periodic direction of the lenses to besubstantially parallel or substantially orthogonal to an extendingdirection of the outer shape reference and to allow the extendingdirection of the outer shape reference to be inclined with respect tothe long-axis direction or the short-axis direction.

-   (5)

The illumination device according to any one of (1) to (4), furtherincluding a second fly-eye lens in an optical path between the lightsource and the light valve, wherein

the first fly-eye lens is disposed closer to the light source than thesecond fly-eye lens.

-   (6)

The illumination device according to any one of (1) to (5), wherein thefirst fly-eye lens includes the plurality of lenses on one of lightentry side and light exit side or both, and

when the plurality of lenses are included on the light entry side, aperiodic direction of the lenses on the light entry side is inclinedwith respect to the long-axis direction or the short-axis direction.

-   (7)

The illumination device according to any one of (1) to (6), furtherincluding a housing that is allowed to contain the light source and thefirst fly-eye lens, wherein a periodic direction of the lenses in thefirst fly-eye lens is inclined with respect to a mounting surface of thehousing.

-   (8)

The illumination device according to any one of (1) to (7), wherein theplurality of lenses in the first fly-eye lens each have a regularhexagonal planar shape in a plane where the lenses are disposed, and arearranged in a honeycomb fashion as a whole.

-   (9)

The illumination device according to (8), wherein an inclination anglebetween a periodic direction of the lenses in the first fly-eye lens andthe long-axis direction or the short-axis direction is greater than 0degrees and smaller than 30 degrees.

-   (10)

The illumination device according to (9), wherein the inclination angleis 15 degrees.

-   (11)

The illumination device according to any one of (1) to (10), wherein thelight source includes one or more laser diodes that emit light of a samewavelength or a different wavelength.

-   (12)

The illumination device according to any one of (1) to (11), wherein theplanar shape of the illumination target region is a rectangular shape,and the first reference direction is a direction along a side of therectangular shape.

-   (13)

An illumination device, including:

a light source; and

a uniform illumination optical system including a first fly-eye lensthat includes a plurality of lenses two-dimensionally arranged andallows light based on emitted light from the light source to passthrough the first fly-eye lens, wherein

light entering the first fly-eye lens has directivity, and

the first fly-eye lens has an outer shape reference linearly extendingalong one direction in a portion of its outer edge, and is disposed toallow a periodic direction of an array of the lenses to be inclined withrespect to an extending direction of the outer shape reference and toallow the extending direction of the outer shape reference to besubstantially parallel to a long-axis direction or a short-axisdirection of an intensity distribution shape of the light entering thefirst fly-eye lens.

-   (14)

An illumination device, including:

a light source; and

a uniform illumination optical system including a first fly-eye lensthat includes a plurality of lenses two-dimensionally arranged andallows light based on emitted light from the light source to passthrough the first fly-eye lens, wherein

light entering the first fly-eye lens has directivity, and

the first fly-eye lens has an outer shape reference linearly extendingalong one direction in a portion of its outer edge, and is disposed toallow a periodic direction of an array of the lenses to be substantiallyparallel or substantially orthogonal to an extending direction of theouter shape reference and to allow the extending direction of the outershape reference to be inclined with respect to a long-axis direction ora short-axis direction of an intensity distribution shape of the lightentering the first fly-eye lens.

-   (15)

An illumination device, including:

a light source;

a uniform illumination optical system including a first fly-eye lensthat includes a plurality of lenses two-dimensionally arranged andallows light based on emitted light from the light source to passthrough the first fly-eye lens; and

a housing that is allowed to contain the light source and the firstfly-eye lens, wherein

light entering the first fly-eye lens has directivity, and

a periodic direction of an array of the lenses in the first fly-eye lensis inclined with respect to a mounting surface of the housing.

-   (16)

A display unit provided with an illumination optical system, a lightvalve, and a projection lens, the light valve that modulatesillumination light from the illumination optical system on a basis of animage signal to emit the thus-modulated light, the projection lens thatprojects the light from the light valve toward a projection surface, theillumination optical system including:

a light source; and

a uniform illumination optical system including a first fly-eye lensthat includes a plurality of lenses two-dimensionally arranged andallows light based on emitted light from the light source to passthrough the first fly-eye lens, wherein

light entering the first fly-eye lens has directivity,

a first reference direction in a planar shape of an illumination targetregion extends along a direction substantially parallel to a long-axisdirection or a short-axis direction of an intensity distribution shapeof the light entering the first fly-eye lens, and

a periodic direction of an array of the lenses in the first fly-eye lensis inclined with respect to the long-axis direction or the short-axisdirection.

-   (17)

The display unit according to (16), wherein the illumination targetregion is an effective region of the light valve.

-   (18)

The display unit according to (17), wherein

a planar shape of the effective region is a rectangular shape, and

the first reference direction is a direction along a side of therectangular shape.

The present application is based on and claims priority from JapanesePatent Application No. 2014-196721 filed in the Japan Patent Office onSep. 26, 2014, the entire contents of which is hereby incorporated byreference.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

The invention claimed is:
 1. An illumination device, comprising: a lightsource; and an optical system configured to include one fly-eye lensthat includes a plurality of lenses, wherein a first reference directionin a planar shape of an illumination target region extends along adirection substantially parallel to a long-axis direction or ashort-axis direction of an intensity distribution shape of the lightentering the one fly-eye lens, the intensity distribution shape of thelight entering the one fly-eye lens is elongated in the long-axisdirection, a periodic direction of an array of the lenses in the onefly-eye lens is inclined with respect to the long-axis direction or theshort-axis direction, wherein the one fly-eye lens has an outer shapereference linearly extending along one direction in a portion of itsouter edge, the plurality of lenses in the one fly-eye lens each have aregular hexagonal planar shape in a plane where the lenses are disposed,and are arranged in a honeycomb pattern as a whole, the periodicdirection of the hexagonal shape lenses in the honeycomb pattern isinclined with respect to the long-axis direction or the short-axisdirection without shifting of the hexagonal shape lenses in thehoneycomb pattern, and an inclination angle between a periodic directionof the lenses in the one fly-eye lens and the long-axis direction or theshort-axis direction is greater than 0 degrees and smaller than 30degrees.
 2. The illumination device according to claim 1, wherein theone fly-eye lens is disposed to allow a periodic direction of the lensesto be inclined with respect to an extending direction of the outer shapereference and to allow the extending direction of the outer shapereference to be substantially parallel to the long-axis direction or theshort-axis direction.
 3. The illumination device according to claim 1,wherein the one fly-eye lens is disposed to allow a periodic directionof the lenses to be substantially parallel or substantially orthogonalto an extending direction of the outer shape reference and to allow theextending direction of the outer shape reference to be inclined withrespect to the long-axis direction or the short-axis direction.
 4. Theillumination device according to claim 1, further comprising anotherfly-eye lens in an optical path between the light source and the lightvalve, wherein the one fly-eye lens is disposed closer to the lightsource than the other fly-eye lens.
 5. The illumination device accordingto claim 1, wherein the one fly-eye lens includes the plurality oflenses on one of light entry side and light exit side or both, and whenthe plurality of lenses are included on the light entry side, a periodicdirection of the lenses on the light entry side is inclined with respectto the long-axis direction or the short-axis direction.
 6. Theillumination device according to claim 1, further comprising a housingthat is allowed to contain the light source and the one fly-eye lens,wherein a periodic direction of the lenses in the one fly-eye lens isinclined with respect to a mounting surface of the housing.
 7. Theillumination device according to claim 1, wherein the inclination angleis 15 degrees.
 8. The illumination device according to claim 1, whereinthe light source includes one or more laser diodes that emit light of asame wavelength or a different wavelength.
 9. The illumination deviceaccording to claim 1, wherein the planar shape of the illuminationtarget region is a rectangular shape, and the first reference directionis a direction along a side of the rectangular shape.
 10. A displaydevice comprising: an illumination optical system; a light valve; and aprojection lens, wherein the illumination optical system includes alight source, an optical system including one fly-eye lens that includesa plurality of lenses, wherein a first reference direction in a planarshape of an illumination target region extends along a directionsubstantially parallel to a long-axis direction or a short-axisdirection of an intensity distribution shape of the light entering theone fly-eye lens, the intensity distribution shape of the light enteringthe one fly-eye lens is elongated in the long-axis direction, a periodicdirection of an array of the lenses in the one fly-eye lens is inclinedwith respect to the long-axis direction or the short-axis direction, theplurality of lenses in the one fly-eye lens each have a regularhexagonal planar shape in a plane where the lenses are disposed, and arearranged in a honeycomb pattern as a whole, the periodic direction ofthe hexagonal shape lenses in the honeycomb pattern is inclined withrespect to the long-axis direction or the short-axis direction withoutshifting of the hexagonal shape lenses in the honeycomb pattern, and aninclination angle between a periodic direction of the lenses in the onefly-eye lens and the long-axis direction or the short-axis direction isgreater than 0 degrees and smaller than 30 degrees.
 11. The displaydevice according to claim 10, wherein the one fly-eye lens has an outershape reference linearly extending along one direction in a portion ofits outer edge and wherein the one fly-eye lens is disposed to allow aperiodic direction of the lenses to be inclined with respect to anextending direction of the outer shape reference and to allow theextending direction of the outer shape reference to be substantiallyparallel to the long-axis direction or the short-axis direction.
 12. Thedisplay unit according to claim 10, wherein the illumination targetregion is an effective region of the light valve.
 13. The display unitaccording to claim 12, wherein a planar shape of the effective region isa rectangular shape, and the first reference direction is a directionalong a side of the rectangular shape.
 14. The display device accordingto claim 10, wherein the light valve modulates illumination light fromthe illumination optical system on a basis of an image signal to emitmodulated light, and the projection lens projects the modulated lightfrom the light valve toward a projection surface.